This invention relates to a connector, a method of manufacturing the connector and an apparatus for manufacturing the connector and, in particular, to a thin low-profile type connector, such as a connector for connection to a liquid-crystal substrate.
Conventionally, a press-in or insert molding method is widely used in order to fix contacts of a connector to an insulator.
On the other hand, thin displays such as liquid-crystal displays have become common in recent years. Such thin displays are widely used, for example, as large-screen displays such as those of TV sets or small-screen displays such as those of mobile phones.
As a result of this trend, it is required that a connector for connection to a display has a thinner shape, a lower profile and a smaller size.
However, there is a problem that, if an attempt is made to manufacture a connector fulfilling the above-mentioned requirement, using a conventional press-in or insert molding method, the insulator used therein will be too thin to ensure sufficient force to hold the contacts of the connector.
As another problem, the insert molding is not suitable when it is desired to provide the contacts with a spring function.
In order to avoid the above-mentioned problems, proposal is made of a structure in which contacts are interposed between two insulators, and the insulators are welded to each other by a laser or the like.
With this structure, one of the insulators, namely, a base insulator is provided with projections (holders) holding the contacts therebetween. Each contact is inserted between these projections and the other insulator, namely, a cover insulator is welded to the projections, whereby the insulators are welded to each other.
The above-mentioned welding structure, however, requires preventing welding defects.
As the preventing welding defects, JP-A-2006-49118 (Patent Document 1) discloses a structure in which each contact is provided with a notch so that a melted insulator flows into the notch.
Although the technology of Patent Document 1 is successful in reducing the chance of occurrence of welding defects, a destructive inspection is required to determine whether or not any welding defects have actually occurred.
In order to solve this problem, as shown in FIG. 22A and FIG. 22B, a connector 101 is proposed in which openings 7c are provided on the opposite sides of each holder 8 such that a contact 3 is interposed between these openings, so that welding defects can be visually detected by observing an amount of molten resin which has flown into the openings 7c. An example of a connector having such a structure is disclosed in Japanese Patent No. 4030121 (JP-B-4030121) (Patent Document 2).